干旱区生态环境知识资源中心

Establishment of lithofacies and interpretation of depositional environment of the Lameta Formation have been carried out for a new area having three nearby exposures. Overall, the successions are broadly differentiable into three major units, i.e. arenaceous in the lower part, argillaceous in middle and calcareous at the top, which more or less serve as three lithofacies associations. Each association consists of various lithofacies which are identified and established on the basis of field observations, added with significant petrological details. The arenaceous association includes five lithofacies, viz. massive sandstone lithofacies; green sandstone lithofacies; thinly bedded, yellowish orange and greyish brown sandstone lithofacies; coarse-grained sandstone lithofacies and dark brown bioturbated sandstone lithofacies. The argillaceous lithofacies association consists of yellowish-brownish-greenish clay-siltstone lithofacies and light grey silty-clay with concretions lithofacies, whereas the calcareous lithofacies association is represented by calcrete lithofacies, nodular limestone lithofacies, chertified limestone lithofacies and intraformational breccia lithofacies. The facies analysis reveals that the deposition of Late Cretaceous Lameta sediments took place in fluvial-lacustrine environments in semi arid condition.